1. Field of the Invention
The present invention relates to methods and apparatus for achieving endoluminal access for instruments, e.g. tubular, fiberoptic instruments, such as colonoscopes, gastroscopes, and the like. More particularly, the present invention relates to methods and apparatus for achieving endoluminal access via anatomical pleating.
2. Description of the Background Art
A physician performing a gastrointestinal examination or treatment commonly advances a colonoscope through a patient's anus into the patient's colon. In order to permit full examination of the colon, the colonoscope must be advanced up to the cecum. Advancement may be directed via a steerable distal end portion of the colonoscope. However, at bends in the colon—namely at the sigmoid, and especially at the two colonic flexures—advancement problems regularly occur, including a risk of injury, pain to the patient, cramp-like contractions of the colon, and even an inability to further advance the colonoscope.
Such problems stem from the fact that the colon is soft and weakly adhered to the abdomen. After a first deflection of the colonoscope, a principal direction of force by which the colonoscope is advanced no longer points towards the distal end of the colonoscope, but rather points towards the readily yielding wall of the colon. Force application is unpleasant to the patient and precludes access to the cecum in about 10% to 15% of all cases.
The concept of pleating or “accordionizing” the colon to facilitate advancement of the colonoscope is described by Eubanks et al. in Mastery of Endoscopic and Laparascopic Surgery, Eubanks, Swantrom, Soper, pg. 337, 2000, Lippincott Williams & Wilkins.                “If the colon were a simple noncompliant tube without redundancy or irregularity, colonoscopic intubation would be a rather simple endeavor of advancing the scope while following the tip. Occasionally, especially if there has been a prior sigmoid resection, colonoscopy may be no more demanding than simple scope advancement. However straight advancement usually promotes the development of loops, stretching the colon. When progression of the scope is not impeded by severe tip deflection, the colon can be encouraged to accordionize along the length of the scope. This is most likely to occur if the scope is repeatedly advanced and withdrawn. In some areas, particularly distally, this is most effective if it is performed with small rapid strokes, referred to as dithering the scope. Elsewhere, such as the transverse colon, this maneuver is performed with long, gentle strokes of 30 to 50 cm.”        
FIGS. 1-3 describe Prior Art methods of accomplishing such accordionization or pleating, as described by Eubanks et al. In FIG. 1, elongation intubation of colon C through anus A is described using colonoscope 10 having steerable deflection tip 12. In FIG. 1A, scope 10 is advanced into proximal sigmoid S. Deflection tip 12 then is turned into the distal descending colon DC, as in FIG. 1B. In FIG. 1C, sigmoid S is accordionized onto scope 10 via simultaneous clockwise torqueing, shaft withdrawal and flattening of deflection tip 12. Further distal advancement of scope 10 then is achievable without causing pain to the patient, etc.
FIG. 2 describe intubation via looping. In FIG. 2A, scope 10 is inserted into sigmoid S with counterclockwise torqueing during scope advancement. In FIG. 2B, the broad loop in the sigmoid flattens the sigmoid-descending colon junction. Subsequent clockwise rotation of scope 10 with concurrent withdrawal accordionizes sigmoid S onto the scope.
FIG. 3 describe intubation of ascending colon AC. In FIG. 3A, scope 10 has a view of the ascending colon with sharp angulation in the right colic flexure F. In FIG. 3B, transverse colon TC is elevated into the upper abdomen via clockwise torqueing and withdrawal of scope 10. As seen in FIG. 3C, scope 10 is then advanced via clockwise torqueing of the scope, flattening of deflection tip 12 and evacuation of air from the distended colon C, thereby accordionizing the colon onto the scope. Complete intubation of cecum Ce then is achieved by further advancing scope 10, as in FIG. 3D.
According to Eubanks et al., accordionization most consistently enables examination of the greatest length of colon with the least amount of scope. In contrast to techniques where the scope is advanced up into the colon, accordionization should be viewed as bringing the colon down over the scope.                “This technique employs simultaneous application of both dithering and torqueing. While the shaft is being advanced approximately 6 to 10 cm, a small amount of counterclockwise torque of about 45 to 60 degrees is applied. The process is reversed by applying clockwise torque and simultaneous withdrawal of the scope for the same length. This cycle is repeated in a rhythmic manner at a rate of about one cycle per second, but without advancement of the shaft. It is useful to hold the shaft of the scope close to the anus to avoid over-advancing. Although the first few dithering/torquing cycles may appear to accomplish little, by rhythmically continuing this motion, the cumulative effect is to pleat a short segment of sigmoid colon onto the scope. As one acquires experience with this technique, it soon becomes apparent that the cyclic rhythm, amount of torque, degree of tip deflection, and shaft advancement distance are all variables that can by altered to achieve maximum effect. If this technique is successful, the descending colon can be readily intubated as far as the splenicflexure by applying clockwise torque during shaft advancement with minimal deflection of the tip. With this approach, the endoscopist is attempting to straighten the colon as he or she progresses, rather than intentionally creating a loop that has to be removed later. Several principles should be kept in mind when this technique is performed:        1. This method should be started early in the process of intubation in the rectosigmoid to minimize the deflection angle.        2. It is not always necessary to see the entire lumen, but one should avoid pushing directly into the colonic wall.        3. The endoscopist should resist the temptation to advance the scope as soon as the lumen is seen, and should continue with this process to maximize the accordionization of the entire sigmoid colon.        4. Excessive gas insufflation is a deterrent to accordionization.        5. If this technique is not successful, one can proceed with intentional looping.”        
As will be apparent, the accordionization technique described by Eubanks et al. requires significant skill and experience on the part of the endoscopist in order to be successful. Furthermore, many variables must be taken into account in order to properly accordionize the colon, including cyclic rhythm, amount of torque, degree of tip deflection, and shaft advancement distance. It is expected that these limitations will hamper broad acceptance of accordionization techniques.
In view of the aforementioned limitations, it would be desirable to provide methods and apparatus for pleating the colon that require less skill and experience on the part of the endoscopist.
It also would be desirable to provide methods and apparatus that simplify and expedite pleating.